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### Table of Contents

I. Introduction ............................................................................................................... ................ 3

A. General Background ......................................................................................................... .. 4

II. Scientific Assessments .................................................................................................... ......... 4

B. Environmental Assessment ................................................................................................. 4 Threatened and Endangered Species ...................................................................................... 5

C. Human Health Assessment ................................................................................................. 5

D. Endocrine Disruptor Screening Program ............................................................................ 6

III. Registration Review Decision ............................................................................................. ... 63 I. Introduction

This document is the Environmental Pr otection Agency’s (EPA or the Agency) Registration Review Decision for undecylenic acid (UDA) which is being issued pursuant to 40

CFR Sections 155.57 and 155.58. UDA is co-formulate d with dioctyl sodium sulfosuccinate (DSS) for which a separate registration review decision has been issued, located in the DSS Registration Review docket, EPA-HQ-OPP-2010-1006. A registration review decision is the Agency’s determination that a pesticide meets, or does not meet, the standard for registration in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).

FIFRA, as amended by the Food Quality Pr otection Act (FQPA) of 1996, mandated the continuous review of existing pestic ides. All pesticides distributed or sold in the United States must generally be registered by EPA, based on sc ientific data showing that they will not cause

unreasonable risks to human health or the envi ronment when used as directed on product labeling. The registration review program is intende d to make sure that, as the ability to assess and reduce risk evolves and as polic ies and practices change, all regi stered pesticides continue to meet the statutory standard of no unreasonabl e adverse effects to human health or the environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the registration review prog ram, the Agency periodically r eevaluates pesticides to make sure that as change occurs, products in the mark etplace can be used safely. Information on this program is provided at: http://www.epa.gov/oppsrr d1/registration_review/

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In 2006, the Agency implemented the Registration Review program pursuant to FIFRA section 3(g) and will review each registered pesticide every 15 years to determine whether it

continues to meet the FIFRA standard for registration. Pursuant to 40 CFR § 155.50, the Agency formally initiated registration review for UDA (Case 4095). The following timeline highlights significant events that have occurr ed during the registration review of UDA:

 December 21, 2011– Publication of the UDA Summary Document that included the Preliminary Work Plan (PWP), and was accompanied by the ecological Problem

Formulation and the human health Scoping Documentin the docket (EPA-HQ-OPP2011-0910) for a 60-day public comment period.

 April 18, 2012– Final Work Plan (FWP) for UDA is signed. No public comments were received during the 60-day comment period on the UDA S ummary Document . In the PWP, EPA specifically solicited comments on environmental justice, water quality concerns, and trade irritant s. The FWP notes that no a dditional ecological or human health data were expected to be needed fo r UDA registration review because sufficient information was available to conduct qualitati ve risk assessments to support a proposed registration review decision, pursu ant to 40 CFR Section 155.53(b).

 March 7, 2013 – Publication of Undecylenic Acid Summary of Human Health Risk Assessment in Support of Registration Review 1 and Preliminary Environmental Fate and Ecological Risk Assessment for the Registra tion of Dioctyl Sodium Sulfosuccinate (Case

1 http://www.regulations.gov/#!document Detail;D=EPA-HQ-OPP-2011-0910-00044 #4029) and Undecylenic Acid (Case #4095) 2 for a 60-day public comment period; no public comments were received.

 June 4, 2014 –The Undecylenic Acid (UDA) Propos ed Registration Review Decision 3 published in the Federal Register (79 FR 32284) (FRL-9911-16) for a 60 day comment period. One comment was received during th e comment period, from the Center for Biological Diversity, concurring with the Ag ency’s “no effect” determination under the Endangered Species Act (ESA) for all listed sp ecies and designated critical habitat for such species. Endangered species are discussed further below.

The documents cited above and additional information on UDA can be found in EPA’s public docket (EPA-HQ-OPP-2011-0910) at www.regulations.gov

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A. General Background

UDA is an insecticide and miticide in shampoos and spray products registered for indoor use on pets including dogs, cats, pup pies, kittens, and reptiles to kill mites and fleas on contact. The first pesticide product containing UDA wa s registered in 1986. These products may be applied to the pet’s coat or to bedding and terrarium surfaces. UDA is co-formulated with the active ingredient dioctyl sodium sulfosuccinate (DSS). UDA is an organi c unsaturated fatty acid

that has structural similarities to those found in the human diet.

In addition to its pesticidal uses register ed by EPA, UDA has other uses in unrelated products; exposure to UDA is dominated by these non-pesticidal uses. UDA has antifungal properties and is approved by the U.S. Food and Drug Administration (FDA) as an over-thecounter drug to treat various skin conditions in humans. It is also used as a fragrance, as a flavoring ingredient, is present in human sweat, and is classified as “Generally Recognized as Safe” (GRAS) by the Food and Drug Administration.

II. Scientific Assessments

B. Environmental Assessment

A summary of the Agency’s environmenta l risk assessment is presented below. For a detailed discussion, see the Preliminary Ecological Risk Asse ssment for the Registration of Dioctyl Sodium Sulfosuccinate (Case #4029) and Undecylenic Acid (Case #4095) noted above. The Agency’s risk assessment evaluated the ac tive ingredients from tw o different registration review cases, DSS and UDA, which are regi stered for use as co-formulated pet shampoo products. The findings of the assessment are app licable to both Registra tion Review cases.

UDA is not expected to persist in the environment; it is a na turally occurring unsaturated fatty acid that is expected to readily biodegrade into shorter chain fatty acids and carbon dioxide. Terrestrial exposure is not expected to result from indoor usage and was not assessed. UDA has

2 http://www.regulations.gov/#!document Detail;D=EPA-HQ-OPP-2011-0910-0009

3 Available at5 the potential to enter waterways through wastewater treatment plan ts (WWTPs) after use as a pet shampoo. Risks to aquatic taxa were assessed.

The EPA Office of Pollution Prevention and Toxics (OPPT) Down the Drain module EFast 4 was used to estimate DSS/UDA concentratio ns in receiving waters based on confidential production data and assumptions of 24% WWTP removal and no dilution. Toxicity endpoints were estimated using Quantitative Structure Ac tivity Relationship (QSA R) predictive modeling.

The estimated environmental c oncentration of UDA is orders of magnitude below the QSAR estimated concentration expected to cause adverse effects in aquatic organisms. Therefore, risk to aquatic taxa is not expected.

Threatened and Endangered Species

There is no exposure to non-targ et terrestrial organisms, a nd the Agency has determined

that there is minimal risk of a dverse effects to non-target aquati c organisms. Therefore, EPA has made a “no effect” determination under the Endange red Species Act (ESA) for all listed species and designated critical habitat for such species, and has theref ore concluded that consultation

with the Fish and Wildlife Service and the Natio nal Marine Fisheries Service under ESA section 7(a)(2) is not required.

C. Human Health Assessment

The Agency considered the most recent hum an health risk assessment, the HED scoping document, and the most updated Agency science policies and risk assessment methodologies to prepare a qualitative risk assessment in support of the registration review of UDA. The most recent human health risk assessment was conducted in 1995. Because of the limited uses, minimal potential for exposure, low toxicity, an d its use as a pharmaceutical drug, the Agency determined that a quantitative human health ri sk assessment was not required under registration review. For a detailed discussion, see the Undecylenic Acid Summary of Human Health Risk Assessment in Support of Registration Review noted above. A summary of the Agency’s human health risk assessment is presented below.

There are no dietary, residen tial, occupational, or aggreg ate risks of concern for UDA. All toxicity data requirements were waived wh en UDA was registered, except for acute toxicity studies; therefore endpoints have not been selected for UDA. UDA has no registered food uses as a pesticide and no residue chemistry data were required or submitted. There are no tolerances

established for UDA and no Canadian or Codex MR Ls. Based on registered uses, drinking water is not a concern. Since no quantitative risk a ssessment was required unde r registration review due to the low toxicity of UDA, quantitative residential handler , occupational, post-application exposure and aggregate assessments were not re quired. It has not been determined that UDA

shares a common mechanism of to xicity with other chemicals; therefore a cumulative risk assessment was also not required.

4 http://www.epa.gov/oppt/exposure/index.htm6 D. Endocrine Disruptor Screening Program

Pursuant to FFDCA Section 408(p)(4), EPA has exempted UDA from the requirements

of the EDSP in an Administrative Order entitled Exemption of Dioctyl Sodium Sulfosuccinate (DSS) and Undecylenic Acid ( UDA) from the Requirements of the Endocrine Disruptor Screening Program , dated April 11, 2014. The Order is available in the docket for this registration review at EP A-HQ-OPP-2011-0910. The Administra tive Order describes the analysis and rationale that the Agency used to evaluate UDA in order to determine that it qualifies for the exemption.

III. Registration Review Decision

In accordance with 40 CFR Sections 155.57 and 155.58, the Agency is issuing this Registration Review Decision document, thus c oncluding the registratio n review for UDA. In addition, EPA does not expect UDA to have direct or indirect a dverse effects to non-listed and listed species or to adversely modify any designa ted critical habitat fo r such species. EPA has

made a “no effect” determination under the ESA fo r all listed species a nd designated critical habitat for such species. Further, the Agency has also determined that based on its structure, chemical nature, and history of uses for human consumption and pharmaceutical applications, UDA is exempt from the EDSP requirement . EPA’s Registration Review Decision determination for UDA is that the pesticide m eets the standard for registration under FIFRA.